This invention relates generally to a lightweight hub structure, and more particularly to a hub structure including a space frame with truss members that is particularly suitable for use in wind turbine generators.
Monolithic shell structures with large cutouts are structurally inefficient and wasteful of material to produce. Moreover, large cutouts in monolithic shells result in stress concentrations, which further exacerbate structural inefficiency.
At least one known hub for a wind turbine includes a casting having a weight of approximately 68,000 pounds. This hub requires extensive machining to match multiple component interfaces. One known hub configuration typically has five large cutouts, including three for blade attachments, one for an output shaft, and one for a spinner. The combined weight of the hub plus the interfaced components, including pitch-drive mechanisms, can approach 100,000 pounds. Structural inefficiency equates to excessive weight, and for structures such as wind turbines that are mounted on supporting towers, these supporting towers must be designed with capacity to support the excess weight.